X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fclient.c;h=8a2ef85b7345c33d89cd2914134bd075a71b4e9e;hp=f0b0efd3c3d86d89fee6184087baa896e40d62c4;hb=d7b377ed1acd4043bde353d99122e0e56fa4e975;hpb=f19f5c968f63a83a83c47390020e6ff0dd7c85aa

diff --git a/src/bin/lttng-sessiond/client.c b/src/bin/lttng-sessiond/client.c
index f0b0efd3c..8a2ef85b7 100644
--- a/src/bin/lttng-sessiond/client.c
+++ b/src/bin/lttng-sessiond/client.c
@@ -1,34 +1,36 @@
 /*
- * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
- *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *               2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include <stddef.h>
-#include <pthread.h>
-#include <signal.h>
-#include <sys/stat.h>
+#include "common/buffer-view.h"
+#include "common/compat/socket.h"
+#include "common/dynamic-buffer.h"
+#include "common/dynamic-array.h"
+#include "common/payload.h"
+#include "common/payload-view.h"
+#include "common/fd-handle.h"
+#include "common/sessiond-comm/sessiond-comm.h"
+#include "common/payload.h"
+#include "common/payload-view.h"
+#include "lttng/lttng-error.h"
+#include "lttng/tracker.h"
 #include <common/compat/getenv.h>
+#include <common/tracker.h>
 #include <common/unix.h>
 #include <common/utils.h>
-#include <lttng/userspace-probe-internal.h>
 #include <lttng/event-internal.h>
-#include <lttng/session-internal.h>
 #include <lttng/session-descriptor-internal.h>
-#include <lttng/tracker-internal.h>
+#include <lttng/session-internal.h>
+#include <lttng/userspace-probe-internal.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stddef.h>
+#include <sys/stat.h>
 
 #include "client.h"
 #include "lttng-sessiond.h"
@@ -82,42 +84,99 @@ static int setup_lttng_msg(struct command_ctx *cmd_ctx,
 {
 	int ret = 0;
 	const size_t header_len = sizeof(struct lttcomm_lttng_msg);
-	const size_t cmd_header_offset = header_len;
-	const size_t payload_offset = cmd_header_offset + cmd_header_len;
 	const size_t total_msg_size = header_len + cmd_header_len + payload_len;
-
-	free(cmd_ctx->llm);
-	cmd_ctx->llm = zmalloc(total_msg_size);
-
-	if (cmd_ctx->llm == NULL) {
-		PERROR("zmalloc");
-		ret = -ENOMEM;
+	const struct lttcomm_lttng_msg llm = {
+		.cmd_type = cmd_ctx->lsm.cmd_type,
+		.pid = cmd_ctx->lsm.domain.attr.pid,
+		.cmd_header_size = cmd_header_len,
+		.data_size = payload_len,
+	};
+
+	ret = lttng_dynamic_buffer_set_size(&cmd_ctx->reply_payload.buffer, 0);
+	if (ret) {
 		goto end;
 	}
 
-	/* Copy common data */
-	cmd_ctx->llm->cmd_type = cmd_ctx->lsm->cmd_type;
-	cmd_ctx->llm->pid = cmd_ctx->lsm->domain.attr.pid;
-	cmd_ctx->llm->cmd_header_size = cmd_header_len;
-	cmd_ctx->llm->data_size = payload_len;
+	lttng_dynamic_pointer_array_clear(&cmd_ctx->reply_payload._fd_handles);
+
 	cmd_ctx->lttng_msg_size = total_msg_size;
 
-	/* Copy command header */
+	/* Append reply header. */
+	ret = lttng_dynamic_buffer_append(
+			&cmd_ctx->reply_payload.buffer, &llm, sizeof(llm));
+	if (ret) {
+		goto end;
+	}
+
+	/* Append command header. */
 	if (cmd_header_len) {
-		memcpy(((uint8_t *) cmd_ctx->llm) + cmd_header_offset, cmd_header_buf,
-			cmd_header_len);
+		ret = lttng_dynamic_buffer_append(
+				&cmd_ctx->reply_payload.buffer, cmd_header_buf,
+				cmd_header_len);
+		if (ret) {
+			goto end;
+		}
 	}
 
-	/* Copy payload */
+	/* Append payload. */
 	if (payload_len) {
-		memcpy(((uint8_t *) cmd_ctx->llm) + payload_offset, payload_buf,
-			payload_len);
+		ret = lttng_dynamic_buffer_append(
+				&cmd_ctx->reply_payload.buffer, payload_buf,
+				payload_len);
+		if (ret) {
+			goto end;
+		}
+	}
+
+end:
+	return ret;
+}
+
+static int setup_empty_lttng_msg(struct command_ctx *cmd_ctx)
+{
+	int ret;
+	const struct lttcomm_lttng_msg llm = {};
+
+	ret = lttng_dynamic_buffer_set_size(&cmd_ctx->reply_payload.buffer, 0);
+	if (ret) {
+		goto end;
 	}
 
+	/* Append place-holder reply header. */
+	ret = lttng_dynamic_buffer_append(
+			&cmd_ctx->reply_payload.buffer, &llm, sizeof(llm));
+	if (ret) {
+		goto end;
+	}
+
+	cmd_ctx->lttng_msg_size = sizeof(llm);
 end:
 	return ret;
 }
 
+static void update_lttng_msg(struct command_ctx *cmd_ctx, size_t cmd_header_len,
+		size_t payload_len)
+{
+	const size_t header_len = sizeof(struct lttcomm_lttng_msg);
+	const size_t total_msg_size = header_len + cmd_header_len + payload_len;
+	const struct lttcomm_lttng_msg llm = {
+		.cmd_type = cmd_ctx->lsm.cmd_type,
+		.pid = cmd_ctx->lsm.domain.attr.pid,
+		.cmd_header_size = cmd_header_len,
+		.data_size = payload_len,
+	};
+	struct lttcomm_lttng_msg *p_llm;
+
+	assert(cmd_ctx->reply_payload.buffer.size >= sizeof(llm));
+
+	p_llm = (typeof(p_llm)) cmd_ctx->reply_payload.buffer.data;
+
+	/* Update existing header. */
+	memcpy(p_llm, &llm, sizeof(llm));
+
+	cmd_ctx->lttng_msg_size = total_msg_size;
+}
+
 /*
  * Start the thread_manage_consumer. This must be done after a lttng-consumerd
  * exec or it will fail.
@@ -192,7 +251,7 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
 		case LTTNG_CONSUMER64_UST:
 		{
 			if (config.consumerd64_lib_dir.value) {
-				char *tmp;
+				const char *tmp;
 				size_t tmplen;
 				char *tmpnew;
 
@@ -229,7 +288,7 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
 		case LTTNG_CONSUMER32_UST:
 		{
 			if (config.consumerd32_lib_dir.value) {
-				char *tmp;
+				const char *tmp;
 				size_t tmplen;
 				char *tmpnew;
 
@@ -500,6 +559,7 @@ static int create_kernel_session(struct ltt_session *session)
 	session->kernel_session->gid = session->gid;
 	session->kernel_session->output_traces = session->output_traces;
 	session->kernel_session->snapshot_mode = session->snapshot_mode;
+	session->kernel_session->is_live_session = session->live_timer != 0;
 
 	return LTTNG_OK;
 
@@ -519,15 +579,14 @@ static unsigned int lttng_sessions_count(uid_t uid, gid_t gid)
 	struct ltt_session *session;
 	const struct ltt_session_list *session_list = session_get_list();
 
-	DBG("Counting number of available session for UID %d GID %d",
-			uid, gid);
+	DBG("Counting number of available session for UID %d", uid);
 	cds_list_for_each_entry(session, &session_list->head, list) {
 		if (!session_get(session)) {
 			continue;
 		}
 		session_lock(session);
 		/* Only count the sessions the user can control. */
-		if (session_access_ok(session, uid, gid) &&
+		if (session_access_ok(session, uid) &&
 				!session->destroyed) {
 			i++;
 		}
@@ -540,19 +599,19 @@ static unsigned int lttng_sessions_count(uid_t uid, gid_t gid)
 static int receive_userspace_probe(struct command_ctx *cmd_ctx, int sock,
 		int *sock_error, struct lttng_event *event)
 {
-	int fd, ret;
+	int fd = -1, ret;
 	struct lttng_userspace_probe_location *probe_location;
-	const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
-	struct lttng_dynamic_buffer probe_location_buffer;
-	struct lttng_buffer_view buffer_view;
+	struct lttng_payload probe_location_payload;
+	struct fd_handle *handle = NULL;
 
 	/*
-	 * Create a buffer to store the serialized version of the probe
+	 * Create a payload to store the serialized version of the probe
 	 * location.
 	 */
-	lttng_dynamic_buffer_init(&probe_location_buffer);
-	ret = lttng_dynamic_buffer_set_size(&probe_location_buffer,
-			cmd_ctx->lsm->u.enable.userspace_probe_location_len);
+	lttng_payload_init(&probe_location_payload);
+
+	ret = lttng_dynamic_buffer_set_size(&probe_location_payload.buffer,
+			cmd_ctx->lsm.u.enable.userspace_probe_location_len);
 	if (ret) {
 		ret = LTTNG_ERR_NOMEM;
 		goto error;
@@ -561,27 +620,11 @@ static int receive_userspace_probe(struct command_ctx *cmd_ctx, int sock,
 	/*
 	 * Receive the probe location.
 	 */
-	ret = lttcomm_recv_unix_sock(sock, probe_location_buffer.data,
-			probe_location_buffer.size);
+	ret = lttcomm_recv_unix_sock(sock, probe_location_payload.buffer.data,
+			probe_location_payload.buffer.size);
 	if (ret <= 0) {
 		DBG("Nothing recv() from client var len data... continuing");
 		*sock_error = 1;
-		lttng_dynamic_buffer_reset(&probe_location_buffer);
-		ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
-		goto error;
-	}
-
-	buffer_view = lttng_buffer_view_from_dynamic_buffer(
-			&probe_location_buffer, 0, probe_location_buffer.size);
-
-	/*
-	 * Extract the probe location from the serialized version.
-	 */
-	ret = lttng_userspace_probe_location_create_from_buffer(
-				&buffer_view, &probe_location);
-	if (ret < 0) {
-		WARN("Failed to create a userspace probe location from the received buffer");
-		lttng_dynamic_buffer_reset( &probe_location_buffer);
 		ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 		goto error;
 	}
@@ -598,35 +641,35 @@ static int receive_userspace_probe(struct command_ctx *cmd_ctx, int sock,
 		goto error;
 	}
 
-	/*
-	 * Set the file descriptor received from the client through the unix
-	 * socket in the probe location.
-	 */
-	lookup = lttng_userspace_probe_location_get_lookup_method(probe_location);
-	if (!lookup) {
-		ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+	handle = fd_handle_create(fd);
+	if (!handle) {
+		ret = LTTNG_ERR_NOMEM;
 		goto error;
 	}
 
-	/*
-	 * From the kernel tracer's perspective, all userspace probe event types
-	 * are all the same: a file and an offset.
-	 */
-	switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
-	case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
-		ret = lttng_userspace_probe_location_function_set_binary_fd(
-				probe_location, fd);
-		break;
-	case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
-		ret = lttng_userspace_probe_location_tracepoint_set_binary_fd(
-				probe_location, fd);
-		break;
-	default:
-		ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+	/* Transferred to the handle. */
+	fd = -1;
+
+	ret = lttng_payload_push_fd_handle(&probe_location_payload, handle);
+	if (ret) {
+		ERR("Failed to add userspace probe file descriptor to payload");
+		ret = LTTNG_ERR_NOMEM;
 		goto error;
 	}
 
-	if (ret) {
+	fd_handle_put(handle);
+	handle = NULL;
+
+	{
+		struct lttng_payload_view view = lttng_payload_view_from_payload(
+			&probe_location_payload, 0, -1);
+
+		/* Extract the probe location from the serialized version. */
+		ret = lttng_userspace_probe_location_create_from_payload(
+				&view, &probe_location);
+	}
+	if (ret < 0) {
+		WARN("Failed to create a userspace probe location from the received buffer");
 		ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 		goto error;
 	}
@@ -638,8 +681,15 @@ static int receive_userspace_probe(struct command_ctx *cmd_ctx, int sock,
 		goto error;
 	}
 
-	lttng_dynamic_buffer_reset(&probe_location_buffer);
 error:
+	if (fd >= 0) {
+		if (close(fd)) {
+			PERROR("Failed to close userspace probe location binary fd");
+		}
+	}
+
+	fd_handle_put(handle);
+	lttng_payload_reset(&probe_location_payload);
 	return ret;
 }
 
@@ -652,24 +702,6 @@ static int setup_lttng_msg_no_cmd_header(struct command_ctx *cmd_ctx,
 	return setup_lttng_msg(cmd_ctx, payload_buf, payload_len, NULL, 0);
 }
 
-/*
- * Free memory of a command context structure.
- */
-static void clean_command_ctx(struct command_ctx **cmd_ctx)
-{
-	DBG("Clean command context structure");
-	if (*cmd_ctx) {
-		if ((*cmd_ctx)->llm) {
-			free((*cmd_ctx)->llm);
-		}
-		if ((*cmd_ctx)->lsm) {
-			free((*cmd_ctx)->lsm);
-		}
-		free(*cmd_ctx);
-		*cmd_ctx = NULL;
-	}
-}
-
 /*
  * Check if the current kernel tracer supports the session rotation feature.
  * Return 1 if it does, 0 otherwise.
@@ -691,14 +723,32 @@ static int check_rotate_compatible(void)
  *
  * Return lttcomm error code.
  */
-static int send_unix_sock(int sock, void *buf, size_t len)
+static int send_unix_sock(int sock, struct lttng_payload_view *view)
 {
+	int ret;
+	const int fd_count = lttng_payload_view_get_fd_handle_count(view);
+
 	/* Check valid length */
-	if (len == 0) {
-		return -1;
+	if (view->buffer.size == 0) {
+		ret = -1;
+		goto end;
+	}
+
+	ret = lttcomm_send_unix_sock(
+			sock, view->buffer.data, view->buffer.size);
+	if (ret < 0) {
+		goto end;
+	}
+
+	if (fd_count > 0) {
+		ret = lttcomm_send_payload_view_fds_unix_sock(sock, view);
+		if (ret < 0) {
+			goto end;
+		}
 	}
 
-	return lttcomm_send_unix_sock(sock, buf, len);
+end:
+	return ret;
 }
 
 /*
@@ -721,13 +771,13 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 	int need_tracing_session = 1;
 	int need_domain;
 
-	DBG("Processing client command %d", cmd_ctx->lsm->cmd_type);
+	DBG("Processing client command %d", cmd_ctx->lsm.cmd_type);
 
 	assert(!rcu_read_ongoing());
 
 	*sock_error = 0;
 
-	switch (cmd_ctx->lsm->cmd_type) {
+	switch (cmd_ctx->lsm.cmd_type) {
 	case LTTNG_CREATE_SESSION_EXT:
 	case LTTNG_DESTROY_SESSION:
 	case LTTNG_LIST_SESSIONS:
@@ -757,7 +807,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 	}
 
 	if (config.no_kernel && need_domain
-			&& cmd_ctx->lsm->domain.type == LTTNG_DOMAIN_KERNEL) {
+			&& cmd_ctx->lsm.domain.type == LTTNG_DOMAIN_KERNEL) {
 		if (!is_root) {
 			ret = LTTNG_ERR_NEED_ROOT_SESSIOND;
 		} else {
@@ -767,7 +817,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 	}
 
 	/* Deny register consumer if we already have a spawned consumer. */
-	if (cmd_ctx->lsm->cmd_type == LTTNG_REGISTER_CONSUMER) {
+	if (cmd_ctx->lsm.cmd_type == LTTNG_REGISTER_CONSUMER) {
 		pthread_mutex_lock(&kconsumer_data.pid_mutex);
 		if (kconsumer_data.pid > 0) {
 			ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
@@ -782,7 +832,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 	 * this here so we don't have to make the call for no payload at each
 	 * command.
 	 */
-	switch(cmd_ctx->lsm->cmd_type) {
+	switch(cmd_ctx->lsm.cmd_type) {
 	case LTTNG_LIST_SESSIONS:
 	case LTTNG_LIST_TRACEPOINTS:
 	case LTTNG_LIST_TRACEPOINT_FIELDS:
@@ -790,11 +840,12 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 	case LTTNG_LIST_CHANNELS:
 	case LTTNG_LIST_EVENTS:
 	case LTTNG_LIST_SYSCALLS:
-	case LTTNG_LIST_TRACKER_IDS:
+	case LTTNG_SESSION_LIST_ROTATION_SCHEDULES:
+	case LTTNG_PROCESS_ATTR_TRACKER_GET_POLICY:
+	case LTTNG_PROCESS_ATTR_TRACKER_GET_INCLUSION_SET:
 	case LTTNG_DATA_PENDING:
 	case LTTNG_ROTATE_SESSION:
 	case LTTNG_ROTATION_GET_INFO:
-	case LTTNG_SESSION_LIST_ROTATION_SCHEDULES:
 		break;
 	default:
 		/* Setup lttng message with no payload */
@@ -806,7 +857,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 	}
 
 	/* Commands that DO NOT need a session. */
-	switch (cmd_ctx->lsm->cmd_type) {
+	switch (cmd_ctx->lsm.cmd_type) {
 	case LTTNG_CREATE_SESSION_EXT:
 	case LTTNG_LIST_SESSIONS:
 	case LTTNG_LIST_TRACEPOINTS:
@@ -818,14 +869,14 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 		need_tracing_session = 0;
 		break;
 	default:
-		DBG("Getting session %s by name", cmd_ctx->lsm->session.name);
+		DBG("Getting session %s by name", cmd_ctx->lsm.session.name);
 		/*
 		 * We keep the session list lock across _all_ commands
 		 * for now, because the per-session lock does not
 		 * handle teardown properly.
 		 */
 		session_lock_list();
-		cmd_ctx->session = session_find_by_name(cmd_ctx->lsm->session.name);
+		cmd_ctx->session = session_find_by_name(cmd_ctx->lsm.session.name);
 		if (cmd_ctx->session == NULL) {
 			ret = LTTNG_ERR_SESS_NOT_FOUND;
 			goto error;
@@ -842,10 +893,10 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 	 * handled, process that right before so we save some round trip in useless
 	 * code path.
 	 */
-	switch (cmd_ctx->lsm->cmd_type) {
+	switch (cmd_ctx->lsm.cmd_type) {
 	case LTTNG_DISABLE_CHANNEL:
 	case LTTNG_DISABLE_EVENT:
-		switch (cmd_ctx->lsm->domain.type) {
+		switch (cmd_ctx->lsm.domain.type) {
 		case LTTNG_DOMAIN_KERNEL:
 			if (!cmd_ctx->session->kernel_session) {
 				ret = LTTNG_ERR_NO_CHANNEL;
@@ -876,7 +927,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 	/*
 	 * Check domain type for specific "pre-action".
 	 */
-	switch (cmd_ctx->lsm->domain.type) {
+	switch (cmd_ctx->lsm.domain.type) {
 	case LTTNG_DOMAIN_KERNEL:
 		if (!is_root) {
 			ret = LTTNG_ERR_NEED_ROOT_SESSIOND;
@@ -911,7 +962,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 			/* Start the kernel consumer daemon */
 			pthread_mutex_lock(&kconsumer_data.pid_mutex);
 			if (kconsumer_data.pid == 0 &&
-					cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER) {
+					cmd_ctx->lsm.cmd_type != LTTNG_REGISTER_CONSUMER) {
 				pthread_mutex_unlock(&kconsumer_data.pid_mutex);
 				ret = start_consumerd(&kconsumer_data);
 				if (ret < 0) {
@@ -954,7 +1005,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 			/* Create UST session if none exist. */
 			if (cmd_ctx->session->ust_session == NULL) {
 				ret = create_ust_session(cmd_ctx->session,
-						ALIGNED_CONST_PTR(cmd_ctx->lsm->domain));
+						ALIGNED_CONST_PTR(cmd_ctx->lsm.domain));
 				if (ret != LTTNG_OK) {
 					goto error;
 				}
@@ -965,7 +1016,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 			pthread_mutex_lock(&ustconsumer64_data.pid_mutex);
 			if (config.consumerd64_bin_path.value &&
 					ustconsumer64_data.pid == 0 &&
-					cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER) {
+					cmd_ctx->lsm.cmd_type != LTTNG_REGISTER_CONSUMER) {
 				pthread_mutex_unlock(&ustconsumer64_data.pid_mutex);
 				ret = start_consumerd(&ustconsumer64_data);
 				if (ret < 0) {
@@ -994,7 +1045,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 			pthread_mutex_lock(&ustconsumer32_data.pid_mutex);
 			if (config.consumerd32_bin_path.value &&
 					ustconsumer32_data.pid == 0 &&
-					cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER) {
+					cmd_ctx->lsm.cmd_type != LTTNG_REGISTER_CONSUMER) {
 				pthread_mutex_unlock(&ustconsumer32_data.pid_mutex);
 				ret = start_consumerd(&ustconsumer32_data);
 				if (ret < 0) {
@@ -1027,9 +1078,9 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int *sock,
 skip_domain:
 
 	/* Validate consumer daemon state when start/stop trace command */
-	if (cmd_ctx->lsm->cmd_type == LTTNG_START_TRACE ||
-			cmd_ctx->lsm->cmd_type == LTTNG_STOP_TRACE) {
-		switch (cmd_ctx->lsm->domain.type) {
+	if (cmd_ctx->lsm.cmd_type == LTTNG_START_TRACE ||
+			cmd_ctx->lsm.cmd_type == LTTNG_STOP_TRACE) {
+		switch (cmd_ctx->lsm.domain.type) {
 		case LTTNG_DOMAIN_NONE:
 			break;
 		case LTTNG_DOMAIN_JUL:
@@ -1054,13 +1105,12 @@ skip_domain:
 	}
 
 	/*
-	 * Check that the UID or GID match that of the tracing session.
+	 * Check that the UID matches that of the tracing session.
 	 * The root user can interact with all sessions.
 	 */
 	if (need_tracing_session) {
 		if (!session_access_ok(cmd_ctx->session,
-				LTTNG_SOCK_GET_UID_CRED(&cmd_ctx->creds),
-				LTTNG_SOCK_GET_GID_CRED(&cmd_ctx->creds)) ||
+				LTTNG_SOCK_GET_UID_CRED(&cmd_ctx->creds)) ||
 				cmd_ctx->session->destroyed) {
 			ret = LTTNG_ERR_EPERM;
 			goto error;
@@ -1083,20 +1133,20 @@ skip_domain:
 	}
 
 	/* Process by command type */
-	switch (cmd_ctx->lsm->cmd_type) {
+	switch (cmd_ctx->lsm.cmd_type) {
 	case LTTNG_ADD_CONTEXT:
 	{
 		/*
 		 * An LTTNG_ADD_CONTEXT command might have a supplementary
 		 * payload if the context being added is an application context.
 		 */
-		if (cmd_ctx->lsm->u.context.ctx.ctx ==
+		if (cmd_ctx->lsm.u.context.ctx.ctx ==
 				LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
 			char *provider_name = NULL, *context_name = NULL;
 			size_t provider_name_len =
-					cmd_ctx->lsm->u.context.provider_name_len;
+					cmd_ctx->lsm.u.context.provider_name_len;
 			size_t context_name_len =
-					cmd_ctx->lsm->u.context.context_name_len;
+					cmd_ctx->lsm.u.context.context_name_len;
 
 			if (provider_name_len == 0 || context_name_len == 0) {
 				/*
@@ -1112,7 +1162,7 @@ skip_domain:
 				ret = -LTTNG_ERR_NOMEM;
 				goto error;
 			}
-			cmd_ctx->lsm->u.context.ctx.u.app_ctx.provider_name =
+			cmd_ctx->lsm.u.context.ctx.u.app_ctx.provider_name =
 					provider_name;
 
 			context_name = zmalloc(context_name_len + 1);
@@ -1120,7 +1170,7 @@ skip_domain:
 				ret = -LTTNG_ERR_NOMEM;
 				goto error_add_context;
 			}
-			cmd_ctx->lsm->u.context.ctx.u.app_ctx.ctx_name =
+			cmd_ctx->lsm.u.context.ctx.u.app_ctx.ctx_name =
 					context_name;
 
 			ret = lttcomm_recv_unix_sock(*sock, provider_name,
@@ -1141,16 +1191,16 @@ skip_domain:
 		 * names.
 		 */
 		ret = cmd_add_context(cmd_ctx->session,
-				cmd_ctx->lsm->domain.type,
-				cmd_ctx->lsm->u.context.channel_name,
-				ALIGNED_CONST_PTR(cmd_ctx->lsm->u.context.ctx),
+				cmd_ctx->lsm.domain.type,
+				cmd_ctx->lsm.u.context.channel_name,
+				ALIGNED_CONST_PTR(cmd_ctx->lsm.u.context.ctx),
 				kernel_poll_pipe[1]);
 
-		cmd_ctx->lsm->u.context.ctx.u.app_ctx.provider_name = NULL;
-		cmd_ctx->lsm->u.context.ctx.u.app_ctx.ctx_name = NULL;
+		cmd_ctx->lsm.u.context.ctx.u.app_ctx.provider_name = NULL;
+		cmd_ctx->lsm.u.context.ctx.u.app_ctx.ctx_name = NULL;
 error_add_context:
-		free(cmd_ctx->lsm->u.context.ctx.u.app_ctx.provider_name);
-		free(cmd_ctx->lsm->u.context.ctx.u.app_ctx.ctx_name);
+		free(cmd_ctx->lsm.u.context.ctx.u.app_ctx.provider_name);
+		free(cmd_ctx->lsm.u.context.ctx.u.app_ctx.ctx_name);
 		if (ret < 0) {
 			goto error;
 		}
@@ -1158,8 +1208,8 @@ error_add_context:
 	}
 	case LTTNG_DISABLE_CHANNEL:
 	{
-		ret = cmd_disable_channel(cmd_ctx->session, cmd_ctx->lsm->domain.type,
-				cmd_ctx->lsm->u.disable.channel_name);
+		ret = cmd_disable_channel(cmd_ctx->session, cmd_ctx->lsm.domain.type,
+				cmd_ctx->lsm.u.disable.channel_name);
 		break;
 	}
 	case LTTNG_DISABLE_EVENT:
@@ -1174,8 +1224,8 @@ error_add_context:
 		 * the filter payload and encounter an error because the session
 		 * daemon closes the socket without ever handling this data.
 		 */
-		size_t count = cmd_ctx->lsm->u.disable.expression_len +
-			cmd_ctx->lsm->u.disable.bytecode_len;
+		size_t count = cmd_ctx->lsm.u.disable.expression_len +
+			cmd_ctx->lsm.u.disable.bytecode_len;
 
 		if (count) {
 			char data[LTTNG_FILTER_MAX_LEN];
@@ -1191,156 +1241,204 @@ error_add_context:
 				count -= (size_t) ret;
 			}
 		}
-		ret = cmd_disable_event(cmd_ctx->session, cmd_ctx->lsm->domain.type,
-				cmd_ctx->lsm->u.disable.channel_name,
-				ALIGNED_CONST_PTR(cmd_ctx->lsm->u.disable.event));
+		ret = cmd_disable_event(cmd_ctx->session, cmd_ctx->lsm.domain.type,
+				cmd_ctx->lsm.u.disable.channel_name,
+				ALIGNED_CONST_PTR(cmd_ctx->lsm.u.disable.event));
 		break;
 	}
 	case LTTNG_ENABLE_CHANNEL:
 	{
-		cmd_ctx->lsm->u.channel.chan.attr.extended.ptr =
-				(struct lttng_channel_extended *) &cmd_ctx->lsm->u.channel.extended;
+		cmd_ctx->lsm.u.channel.chan.attr.extended.ptr =
+				(struct lttng_channel_extended *) &cmd_ctx->lsm.u.channel.extended;
 		ret = cmd_enable_channel(cmd_ctx->session,
-				ALIGNED_CONST_PTR(cmd_ctx->lsm->domain),
-				ALIGNED_CONST_PTR(cmd_ctx->lsm->u.channel.chan),
+				ALIGNED_CONST_PTR(cmd_ctx->lsm.domain),
+				ALIGNED_CONST_PTR(cmd_ctx->lsm.u.channel.chan),
 				kernel_poll_pipe[1]);
 		break;
 	}
-	case LTTNG_TRACK_ID:
+	case LTTNG_PROCESS_ATTR_TRACKER_ADD_INCLUDE_VALUE:
+	case LTTNG_PROCESS_ATTR_TRACKER_REMOVE_INCLUDE_VALUE:
 	{
-		struct lttng_tracker_id *id = NULL;
-		enum lttng_tracker_id_status status;
-
-		id = lttng_tracker_id_create();
-		if (!id) {
-			ret = LTTNG_ERR_NOMEM;
+		struct lttng_dynamic_buffer payload;
+		struct lttng_buffer_view payload_view;
+		const bool add_value =
+				cmd_ctx->lsm.cmd_type ==
+				LTTNG_PROCESS_ATTR_TRACKER_ADD_INCLUDE_VALUE;
+		const size_t name_len =
+				cmd_ctx->lsm.u.process_attr_tracker_add_remove_include_value
+						.name_len;
+		const enum lttng_domain_type domain_type =
+				(enum lttng_domain_type)
+						cmd_ctx->lsm.domain.type;
+		const enum lttng_process_attr process_attr =
+				(enum lttng_process_attr) cmd_ctx->lsm.u
+						.process_attr_tracker_add_remove_include_value
+						.process_attr;
+		const enum lttng_process_attr_value_type value_type =
+				(enum lttng_process_attr_value_type) cmd_ctx
+						->lsm.u
+						.process_attr_tracker_add_remove_include_value
+						.value_type;
+		struct process_attr_value *value;
+		enum lttng_error_code ret_code;
+
+		/* Receive remaining variable length payload if applicable. */
+		if (name_len > LOGIN_NAME_MAX) {
+			/*
+			 * POSIX mandates user and group names that are at least
+			 * 8 characters long. Note that although shadow-utils
+			 * (useradd, groupaadd, etc.) use 32 chars as their
+			 * limit (from bits/utmp.h, UT_NAMESIZE),
+			 * LOGIN_NAME_MAX is defined to 256.
+			 */
+			ERR("Rejecting process attribute tracker value %s as the provided exceeds the maximal allowed length: argument length = %zu, maximal length = %d",
+					add_value ? "addition" : "removal",
+					name_len, LOGIN_NAME_MAX);
+			ret = LTTNG_ERR_INVALID;
 			goto error;
 		}
 
-		switch (cmd_ctx->lsm->u.id_tracker.id_type) {
-		case LTTNG_ID_ALL:
-			status = lttng_tracker_id_set_all(id);
-			break;
-		case LTTNG_ID_VALUE:
-			status = lttng_tracker_id_set_value(
-					id, cmd_ctx->lsm->u.id_tracker.u.value);
-			break;
-		case LTTNG_ID_STRING:
-		{
-			const size_t var_len = cmd_ctx->lsm->u.id_tracker.u.var_len;
-			char *string = NULL;
-
-			string = zmalloc(var_len);
-			if (!string) {
-				lttng_tracker_id_destroy(id);
+		lttng_dynamic_buffer_init(&payload);
+		if (name_len != 0) {
+			/*
+			 * Receive variable payload for user/group name
+			 * arguments.
+			 */
+			ret = lttng_dynamic_buffer_set_size(&payload, name_len);
+			if (ret) {
+				ERR("Failed to allocate buffer to receive payload of %s process attribute tracker value argument",
+						add_value ? "add" : "remove");
 				ret = LTTNG_ERR_NOMEM;
-				goto error;
+				goto error_add_remove_tracker_value;
 			}
-			DBG("Receiving var len tracker id string from client");
-			ret = lttcomm_recv_unix_sock(*sock, string, var_len);
+
+			ret = lttcomm_recv_unix_sock(
+					*sock, payload.data, name_len);
 			if (ret <= 0) {
-				DBG("Nothing received");
+				ERR("Failed to receive payload of %s process attribute tracker value argument",
+						add_value ? "add" : "remove");
 				*sock_error = 1;
-				free(string);
-				lttng_tracker_id_destroy(id);
-				ret = LTTNG_ERR_INVALID;
-				goto error;
-			}
-			if (strnlen(string, var_len) != var_len - 1) {
-				DBG("String received as tracker ID is not NULL-terminated");
-				free(string);
-				lttng_tracker_id_destroy(id);
-				ret = LTTNG_ERR_INVALID;
-				goto error;
+				ret = LTTNG_ERR_INVALID_PROTOCOL;
+				goto error_add_remove_tracker_value;
 			}
+		}
 
-			status = lttng_tracker_id_set_string(id, string);
-			free(string);
-			break;
+		payload_view = lttng_buffer_view_from_dynamic_buffer(
+				&payload, 0, name_len);
+		/*
+		 * Validate the value type and domains are legal for the process
+		 * attribute tracker that is specified and convert the value to
+		 * add/remove to the internal sessiond representation.
+		 */
+		ret_code = process_attr_value_from_comm(domain_type,
+				process_attr, value_type,
+				&cmd_ctx->lsm.u.process_attr_tracker_add_remove_include_value
+						 .integral_value,
+				&payload_view, &value);
+		if (ret_code != LTTNG_OK) {
+			ret = ret_code;
+			goto error_add_remove_tracker_value;
+		}
+
+		if (add_value) {
+			ret = cmd_process_attr_tracker_inclusion_set_add_value(
+					cmd_ctx->session, domain_type,
+					process_attr, value);
+		} else {
+			ret = cmd_process_attr_tracker_inclusion_set_remove_value(
+					cmd_ctx->session, domain_type,
+					process_attr, value);
 		}
-		default:
-			lttng_tracker_id_destroy(id);
-			ret = LTTNG_ERR_INVALID;
+		process_attr_value_destroy(value);
+	error_add_remove_tracker_value:
+		lttng_dynamic_buffer_reset(&payload);
+		break;
+	}
+	case LTTNG_PROCESS_ATTR_TRACKER_GET_POLICY:
+	{
+		enum lttng_tracking_policy tracking_policy;
+		const enum lttng_domain_type domain_type =
+				(enum lttng_domain_type)
+						cmd_ctx->lsm.domain.type;
+		const enum lttng_process_attr process_attr =
+				(enum lttng_process_attr) cmd_ctx->lsm.u
+						.process_attr_tracker_get_tracking_policy
+						.process_attr;
+
+		ret = cmd_process_attr_tracker_get_tracking_policy(
+				cmd_ctx->session, domain_type, process_attr,
+				&tracking_policy);
+		if (ret != LTTNG_OK) {
 			goto error;
 		}
 
-		if (status != LTTNG_TRACKER_ID_STATUS_OK) {
-			ERR("Invalid value for tracker id");
-			ret = LTTNG_ERR_INVALID;
-			lttng_tracker_id_destroy(id);
+		ret = setup_lttng_msg_no_cmd_header(cmd_ctx,
+				&(uint32_t){tracking_policy}, sizeof(uint32_t));
+		if (ret < 0) {
+			ret = LTTNG_ERR_NOMEM;
 			goto error;
 		}
-
-		ret = cmd_track_id(cmd_ctx->session,
-				cmd_ctx->lsm->u.id_tracker.tracker_type,
-				cmd_ctx->lsm->domain.type, id);
-		lttng_tracker_id_destroy(id);
+		ret = LTTNG_OK;
 		break;
 	}
-	case LTTNG_UNTRACK_ID:
+	case LTTNG_PROCESS_ATTR_TRACKER_SET_POLICY:
 	{
-		struct lttng_tracker_id *id = NULL;
-		enum lttng_tracker_id_status status;
-
-		id = lttng_tracker_id_create();
-
-		switch (cmd_ctx->lsm->u.id_tracker.id_type) {
-		case LTTNG_ID_ALL:
-			status = lttng_tracker_id_set_all(id);
-			break;
-		case LTTNG_ID_VALUE:
-			status = lttng_tracker_id_set_value(
-					id, cmd_ctx->lsm->u.id_tracker.u.value);
-			break;
-		case LTTNG_ID_STRING:
-		{
-			const size_t var_len = cmd_ctx->lsm->u.id_tracker.u.var_len;
-			char *string = NULL;
-
-			string = zmalloc(var_len);
-			if (!string) {
-				ret = LTTNG_ERR_NOMEM;
-				lttng_tracker_id_destroy(id);
-				goto error;
-			}
-			DBG("Receiving var len tracker id string from client");
-			ret = lttcomm_recv_unix_sock(*sock, string, var_len);
-			if (ret <= 0) {
-				DBG("Nothing received");
-				*sock_error = 1;
-				lttng_tracker_id_destroy(id);
-				free(string);
-				ret = LTTNG_ERR_INVALID;
-				goto error;
-			}
-			if (strnlen(string, var_len) != var_len - 1) {
-				DBG("String received as tracker ID is not NULL-terminated");
-				lttng_tracker_id_destroy(id);
-				free(string);
-				ret = LTTNG_ERR_INVALID;
-				goto error;
-			}
-			status = lttng_tracker_id_set_string(id, string);
-			free(string);
-			break;
+		const enum lttng_tracking_policy tracking_policy =
+				(enum lttng_tracking_policy) cmd_ctx->lsm.u
+						.process_attr_tracker_set_tracking_policy
+						.tracking_policy;
+		const enum lttng_domain_type domain_type =
+				(enum lttng_domain_type)
+						cmd_ctx->lsm.domain.type;
+		const enum lttng_process_attr process_attr =
+				(enum lttng_process_attr) cmd_ctx->lsm.u
+						.process_attr_tracker_set_tracking_policy
+						.process_attr;
+
+		ret = cmd_process_attr_tracker_set_tracking_policy(
+				cmd_ctx->session, domain_type, process_attr,
+				tracking_policy);
+		if (ret != LTTNG_OK) {
+			goto error;
 		}
-		default:
-			lttng_tracker_id_destroy(id);
-			ret = LTTNG_ERR_INVALID;
+		break;
+	}
+	case LTTNG_PROCESS_ATTR_TRACKER_GET_INCLUSION_SET:
+	{
+		struct lttng_process_attr_values *values;
+		struct lttng_dynamic_buffer reply;
+		const enum lttng_domain_type domain_type =
+				(enum lttng_domain_type)
+						cmd_ctx->lsm.domain.type;
+		const enum lttng_process_attr process_attr =
+				(enum lttng_process_attr) cmd_ctx->lsm.u
+						.process_attr_tracker_get_inclusion_set
+						.process_attr;
+
+		ret = cmd_process_attr_tracker_get_inclusion_set(
+				cmd_ctx->session, domain_type, process_attr,
+				&values);
+		if (ret != LTTNG_OK) {
 			goto error;
 		}
 
-		if (status != LTTNG_TRACKER_ID_STATUS_OK) {
-			ERR("Invalid tracker id");
-			lttng_tracker_id_destroy(id);
-			ret = LTTNG_ERR_INVALID;
-			goto error;
+		lttng_dynamic_buffer_init(&reply);
+		ret = lttng_process_attr_values_serialize(values, &reply);
+		if (ret < 0) {
+			goto error_tracker_get_inclusion_set;
+		}
+
+		ret = setup_lttng_msg_no_cmd_header(
+				cmd_ctx, reply.data, reply.size);
+		if (ret < 0) {
+			ret = LTTNG_ERR_NOMEM;
+			goto error_tracker_get_inclusion_set;
 		}
+		ret = LTTNG_OK;
 
-		ret = cmd_untrack_id(cmd_ctx->session,
-				cmd_ctx->lsm->u.id_tracker.tracker_type,
-				cmd_ctx->lsm->domain.type, id);
-		lttng_tracker_id_destroy(id);
+	error_tracker_get_inclusion_set:
+		lttng_process_attr_values_destroy(values);
+		lttng_dynamic_buffer_reset(&reply);
 		break;
 	}
 	case LTTNG_ENABLE_EVENT:
@@ -1351,8 +1449,8 @@ error_add_context:
 		char *filter_expression = NULL;
 
 		/* Handle exclusion events and receive it from the client. */
-		if (cmd_ctx->lsm->u.enable.exclusion_count > 0) {
-			size_t count = cmd_ctx->lsm->u.enable.exclusion_count;
+		if (cmd_ctx->lsm.u.enable.exclusion_count > 0) {
+			size_t count = cmd_ctx->lsm.u.enable.exclusion_count;
 
 			exclusion = zmalloc(sizeof(struct lttng_event_exclusion) +
 					(count * LTTNG_SYMBOL_NAME_LEN));
@@ -1375,9 +1473,9 @@ error_add_context:
 		}
 
 		/* Get filter expression from client. */
-		if (cmd_ctx->lsm->u.enable.expression_len > 0) {
+		if (cmd_ctx->lsm.u.enable.expression_len > 0) {
 			size_t expression_len =
-				cmd_ctx->lsm->u.enable.expression_len;
+				cmd_ctx->lsm.u.enable.expression_len;
 
 			if (expression_len > LTTNG_FILTER_MAX_LEN) {
 				ret = LTTNG_ERR_FILTER_INVAL;
@@ -1407,8 +1505,8 @@ error_add_context:
 		}
 
 		/* Handle filter and get bytecode from client. */
-		if (cmd_ctx->lsm->u.enable.bytecode_len > 0) {
-			size_t bytecode_len = cmd_ctx->lsm->u.enable.bytecode_len;
+		if (cmd_ctx->lsm.u.enable.bytecode_len > 0) {
+			size_t bytecode_len = cmd_ctx->lsm.u.enable.bytecode_len;
 
 			if (bytecode_len > LTTNG_FILTER_MAX_LEN) {
 				ret = LTTNG_ERR_FILTER_INVAL;
@@ -1447,10 +1545,10 @@ error_add_context:
 			}
 		}
 
-		ev = lttng_event_copy(ALIGNED_CONST_PTR(cmd_ctx->lsm->u.enable.event));
+		ev = lttng_event_copy(ALIGNED_CONST_PTR(cmd_ctx->lsm.u.enable.event));
 		if (!ev) {
 			DBG("Failed to copy event: %s",
-					cmd_ctx->lsm->u.enable.event.name);
+					cmd_ctx->lsm.u.enable.event.name);
 			free(filter_expression);
 			free(bytecode);
 			free(exclusion);
@@ -1459,7 +1557,7 @@ error_add_context:
 		}
 
 
-		if (cmd_ctx->lsm->u.enable.userspace_probe_location_len > 0) {
+		if (cmd_ctx->lsm.u.enable.userspace_probe_location_len > 0) {
 			/* Expect a userspace probe description. */
 			ret = receive_userspace_probe(cmd_ctx, *sock, sock_error, ev);
 			if (ret) {
@@ -1472,8 +1570,8 @@ error_add_context:
 		}
 
 		ret = cmd_enable_event(cmd_ctx->session,
-				ALIGNED_CONST_PTR(cmd_ctx->lsm->domain),
-				cmd_ctx->lsm->u.enable.channel_name,
+				ALIGNED_CONST_PTR(cmd_ctx->lsm.domain),
+				cmd_ctx->lsm.u.enable.channel_name,
 				ev,
 				filter_expression, bytecode, exclusion,
 				kernel_poll_pipe[1]);
@@ -1486,7 +1584,7 @@ error_add_context:
 		ssize_t nb_events;
 
 		session_lock_list();
-		nb_events = cmd_list_tracepoints(cmd_ctx->lsm->domain.type, &events);
+		nb_events = cmd_list_tracepoints(cmd_ctx->lsm.domain.type, &events);
 		session_unlock_list();
 		if (nb_events < 0) {
 			/* Return value is a negative lttng_error_code. */
@@ -1515,7 +1613,7 @@ error_add_context:
 		ssize_t nb_fields;
 
 		session_lock_list();
-		nb_fields = cmd_list_tracepoint_fields(cmd_ctx->lsm->domain.type,
+		nb_fields = cmd_list_tracepoint_fields(cmd_ctx->lsm.domain.type,
 				&fields);
 		session_unlock_list();
 		if (nb_fields < 0) {
@@ -1566,55 +1664,12 @@ error_add_context:
 		ret = LTTNG_OK;
 		break;
 	}
-	case LTTNG_LIST_TRACKER_IDS:
-	{
-		struct lttcomm_tracker_command_header cmd_header;
-		struct lttng_tracker_ids *ids = NULL;
-		enum lttng_tracker_id_status status;
-		unsigned int nr_ids;
-		struct lttng_dynamic_buffer buf;
-
-		ret = cmd_list_tracker_ids(
-				cmd_ctx->lsm->u.id_tracker.tracker_type,
-				cmd_ctx->session, cmd_ctx->lsm->domain.type,
-				&ids);
-		if (ret != LTTNG_OK) {
-			goto error;
-		}
-
-		lttng_dynamic_buffer_init(&buf);
-
-		status = lttng_tracker_ids_get_count(ids, &nr_ids);
-		if (status != LTTNG_TRACKER_ID_STATUS_OK) {
-			ret = -LTTNG_ERR_INVALID;
-			goto error_list_tracker;
-		}
-
-		cmd_header.nb_tracker_id = nr_ids;
-
-		ret = lttng_tracker_ids_serialize(ids, &buf);
-		if (ret < 0) {
-			goto error_list_tracker;
-		}
-
-		ret = setup_lttng_msg(cmd_ctx, buf.data, buf.size, &cmd_header,
-				sizeof(cmd_header));
-	error_list_tracker:
-		lttng_tracker_ids_destroy(ids);
-		lttng_dynamic_buffer_reset(&buf);
-		if (ret < 0) {
-			goto error;
-		}
-
-		ret = LTTNG_OK;
-		break;
-	}
 	case LTTNG_SET_CONSUMER_URI:
 	{
 		size_t nb_uri, len;
 		struct lttng_uri *uris;
 
-		nb_uri = cmd_ctx->lsm->u.uri.size;
+		nb_uri = cmd_ctx->lsm.u.uri.size;
 		len = nb_uri * sizeof(struct lttng_uri);
 
 		if (nb_uri == 0) {
@@ -1707,7 +1762,7 @@ error_add_context:
 		ssize_t payload_size;
 		struct lttng_channel *channels = NULL;
 
-		payload_size = cmd_list_channels(cmd_ctx->lsm->domain.type,
+		payload_size = cmd_list_channels(cmd_ctx->lsm.domain.type,
 				cmd_ctx->session, &channels);
 		if (payload_size < 0) {
 			/* Return value is a negative lttng_error_code. */
@@ -1728,32 +1783,34 @@ error_add_context:
 	}
 	case LTTNG_LIST_EVENTS:
 	{
-		ssize_t nb_event;
-		struct lttng_event *events = NULL;
-		struct lttcomm_event_command_header cmd_header;
-		size_t total_size;
-
-		memset(&cmd_header, 0, sizeof(cmd_header));
-		/* Extended infos are included at the end of events */
-		nb_event = cmd_list_events(cmd_ctx->lsm->domain.type,
-			cmd_ctx->session, cmd_ctx->lsm->u.list.channel_name,
-			&events, &total_size);
-
-		if (nb_event < 0) {
-			/* Return value is a negative lttng_error_code. */
-			ret = -nb_event;
-			goto error;
+		ssize_t list_ret;
+		struct lttcomm_event_command_header cmd_header = {};
+		size_t original_payload_size;
+		size_t payload_size;
+
+		ret = setup_empty_lttng_msg(cmd_ctx);
+		if (ret) {
+			ret = LTTNG_ERR_NOMEM;
+			goto setup_error;
 		}
 
-		cmd_header.nb_events = nb_event;
-		ret = setup_lttng_msg(cmd_ctx, events, total_size,
-			&cmd_header, sizeof(cmd_header));
-		free(events);
+		original_payload_size = cmd_ctx->reply_payload.buffer.size;
 
-		if (ret < 0) {
-			goto setup_error;
+		/* Extended infos are included at the end of the payload. */
+		list_ret = cmd_list_events(cmd_ctx->lsm.domain.type,
+				cmd_ctx->session,
+				cmd_ctx->lsm.u.list.channel_name,
+				&cmd_ctx->reply_payload);
+		if (list_ret < 0) {
+			/* Return value is a negative lttng_error_code. */
+			ret = -list_ret;
+			goto error;
 		}
 
+		payload_size = cmd_ctx->reply_payload.buffer.size -
+				sizeof(cmd_header) - original_payload_size;
+		update_lttng_msg(cmd_ctx, sizeof(cmd_header), payload_size);
+
 		ret = LTTNG_OK;
 		break;
 	}
@@ -1798,7 +1855,7 @@ error_add_context:
 	{
 		struct consumer_data *cdata;
 
-		switch (cmd_ctx->lsm->domain.type) {
+		switch (cmd_ctx->lsm.domain.type) {
 		case LTTNG_DOMAIN_KERNEL:
 			cdata = &kconsumer_data;
 			break;
@@ -1807,8 +1864,8 @@ error_add_context:
 			goto error;
 		}
 
-		ret = cmd_register_consumer(cmd_ctx->session, cmd_ctx->lsm->domain.type,
-				cmd_ctx->lsm->u.reg.path, cdata);
+		ret = cmd_register_consumer(cmd_ctx->session, cmd_ctx->lsm.domain.type,
+				cmd_ctx->lsm.u.reg.path, cdata);
 		break;
 	}
 	case LTTNG_DATA_PENDING:
@@ -1859,7 +1916,7 @@ error_add_context:
 		struct lttcomm_lttng_output_id reply;
 
 		ret = cmd_snapshot_add_output(cmd_ctx->session,
-				ALIGNED_CONST_PTR(cmd_ctx->lsm->u.snapshot_output.output),
+				ALIGNED_CONST_PTR(cmd_ctx->lsm.u.snapshot_output.output),
 				&snapshot_id);
 		if (ret != LTTNG_OK) {
 			goto error;
@@ -1879,7 +1936,7 @@ error_add_context:
 	case LTTNG_SNAPSHOT_DEL_OUTPUT:
 	{
 		ret = cmd_snapshot_del_output(cmd_ctx->session,
-				ALIGNED_CONST_PTR(cmd_ctx->lsm->u.snapshot_output.output));
+				ALIGNED_CONST_PTR(cmd_ctx->lsm.u.snapshot_output.output));
 		break;
 	}
 	case LTTNG_SNAPSHOT_LIST_OUTPUT:
@@ -1908,8 +1965,8 @@ error_add_context:
 	case LTTNG_SNAPSHOT_RECORD:
 	{
 		ret = cmd_snapshot_record(cmd_ctx->session,
-				ALIGNED_CONST_PTR(cmd_ctx->lsm->u.snapshot_record.output),
-				cmd_ctx->lsm->u.snapshot_record.wait);
+				ALIGNED_CONST_PTR(cmd_ctx->lsm.u.snapshot_record.output),
+				cmd_ctx->lsm.u.snapshot_record.wait);
 		break;
 	}
 	case LTTNG_CREATE_SESSION_EXT:
@@ -1945,14 +2002,14 @@ error_add_context:
 	}
 	case LTTNG_SAVE_SESSION:
 	{
-		ret = cmd_save_sessions(&cmd_ctx->lsm->u.save_session.attr,
+		ret = cmd_save_sessions(&cmd_ctx->lsm.u.save_session.attr,
 			&cmd_ctx->creds);
 		break;
 	}
 	case LTTNG_SET_SESSION_SHM_PATH:
 	{
 		ret = cmd_set_session_shm_path(cmd_ctx->session,
-				cmd_ctx->lsm->u.set_shm_path.shm_path);
+				cmd_ctx->lsm.u.set_shm_path.shm_path);
 		break;
 	}
 	case LTTNG_REGENERATE_METADATA:
@@ -2014,7 +2071,7 @@ error_add_context:
 
 		memset(&get_info_return, 0, sizeof(get_info_return));
 		ret = cmd_rotate_get_info(cmd_ctx->session, &get_info_return,
-				cmd_ctx->lsm->u.get_rotation_info.rotation_id);
+				cmd_ctx->lsm.u.get_rotation_info.rotation_id);
 		if (ret < 0) {
 			ret = -ret;
 			goto error;
@@ -2042,9 +2099,9 @@ error_add_context:
 			goto error;
 		}
 
-		set_schedule = cmd_ctx->lsm->u.rotation_set_schedule.set == 1;
-		schedule_type = (enum lttng_rotation_schedule_type) cmd_ctx->lsm->u.rotation_set_schedule.type;
-		value = cmd_ctx->lsm->u.rotation_set_schedule.value;
+		set_schedule = cmd_ctx->lsm.u.rotation_set_schedule.set == 1;
+		schedule_type = (enum lttng_rotation_schedule_type) cmd_ctx->lsm.u.rotation_set_schedule.type;
+		value = cmd_ctx->lsm.u.rotation_set_schedule.value;
 
 		ret = cmd_rotation_set_schedule(cmd_ctx->session,
 				set_schedule,
@@ -2087,14 +2144,14 @@ error_add_context:
 	}
 
 error:
-	if (cmd_ctx->llm == NULL) {
-		DBG("Missing llm structure. Allocating one.");
+	if (cmd_ctx->reply_payload.buffer.size == 0) {
+		DBG("Missing llm header, creating one.");
 		if (setup_lttng_msg_no_cmd_header(cmd_ctx, NULL, 0) < 0) {
 			goto setup_error;
 		}
 	}
 	/* Set return code */
-	cmd_ctx->llm->ret_code = ret;
+	((struct lttcomm_lttng_msg *) (cmd_ctx->reply_payload.buffer.data))->ret_code = ret;
 setup_error:
 	if (cmd_ctx->session) {
 		session_unlock(cmd_ctx->session);
@@ -2168,14 +2225,16 @@ static void *thread_manage_clients(void *data)
 	int sock = -1, ret, i, pollfd, err = -1;
 	int sock_error;
 	uint32_t revents, nb_fd;
-	struct command_ctx *cmd_ctx = NULL;
 	struct lttng_poll_event events;
 	const int client_sock = thread_state.client_sock;
 	struct lttng_pipe *quit_pipe = data;
 	const int thread_quit_pipe_fd = lttng_pipe_get_readfd(quit_pipe);
+	struct command_ctx cmd_ctx = {};
 
 	DBG("[thread] Manage client started");
 
+	lttng_payload_init(&cmd_ctx.reply_payload);
+
 	is_root = (getuid() == 0);
 
 	pthread_cleanup_push(thread_init_cleanup, NULL);
@@ -2213,7 +2272,7 @@ static void *thread_manage_clients(void *data)
 	}
 
 	/* Set state as running. */
-        set_thread_status(true);
+	set_thread_status(true);
 	pthread_cleanup_pop(0);
 
 	/* This testpoint is after we signal readiness to the parent. */
@@ -2230,6 +2289,14 @@ static void *thread_manage_clients(void *data)
 	while (1) {
 		const struct cmd_completion_handler *cmd_completion_handler;
 
+		cmd_ctx.creds = (lttng_sock_cred) {
+			.uid = UINT32_MAX,
+			.gid = UINT32_MAX,
+		};
+		cmd_ctx.session = NULL;
+		lttng_payload_clear(&cmd_ctx.reply_payload);
+		cmd_ctx.lttng_msg_size = 0;
+
 		DBG("Accepting client command ...");
 
 		/* Inifinite blocking call, waiting for transmission */
@@ -2293,23 +2360,6 @@ static void *thread_manage_clients(void *data)
 			goto error;
 		}
 
-		/* Allocate context command to process the client request */
-		cmd_ctx = zmalloc(sizeof(struct command_ctx));
-		if (cmd_ctx == NULL) {
-			PERROR("zmalloc cmd_ctx");
-			goto error;
-		}
-
-		/* Allocate data buffer for reception */
-		cmd_ctx->lsm = zmalloc(sizeof(struct lttcomm_session_msg));
-		if (cmd_ctx->lsm == NULL) {
-			PERROR("zmalloc cmd_ctx->lsm");
-			goto error;
-		}
-
-		cmd_ctx->llm = NULL;
-		cmd_ctx->session = NULL;
-
 		health_code_update();
 
 		/*
@@ -2318,16 +2368,15 @@ static void *thread_manage_clients(void *data)
 		 * the client.
 		 */
 		DBG("Receiving data from client ...");
-		ret = lttcomm_recv_creds_unix_sock(sock, cmd_ctx->lsm,
-				sizeof(struct lttcomm_session_msg), &cmd_ctx->creds);
-		if (ret <= 0) {
-			DBG("Nothing recv() from client... continuing");
+		ret = lttcomm_recv_creds_unix_sock(sock, &cmd_ctx.lsm,
+				sizeof(struct lttcomm_session_msg), &cmd_ctx.creds);
+		if (ret != sizeof(struct lttcomm_session_msg)) {
+			DBG("Incomplete recv() from client... continuing");
 			ret = close(sock);
 			if (ret) {
 				PERROR("close");
 			}
 			sock = -1;
-			clean_command_ctx(&cmd_ctx);
 			continue;
 		}
 
@@ -2343,7 +2392,7 @@ static void *thread_manage_clients(void *data)
 		 * informations for the client. The command context struct contains
 		 * everything this function may needs.
 		 */
-		ret = process_client_msg(cmd_ctx, &sock, &sock_error);
+		ret = process_client_msg(&cmd_ctx, &sock, &sock_error);
 		rcu_thread_offline();
 		if (ret < 0) {
 			if (sock >= 0) {
@@ -2351,8 +2400,8 @@ static void *thread_manage_clients(void *data)
 				if (ret) {
 					PERROR("close");
 				}
-                        }
-                        sock = -1;
+			}
+			sock = -1;
 			/*
 			 * TODO: Inform client somehow of the fatal error. At
 			 * this point, ret < 0 means that a zmalloc failed
@@ -2360,7 +2409,6 @@ static void *thread_manage_clients(void *data)
 			 * command, unless a socket error has been
 			 * detected.
 			 */
-			clean_command_ctx(&cmd_ctx);
 			continue;
 		}
 
@@ -2371,7 +2419,6 @@ static void *thread_manage_clients(void *data)
 			completion_code = cmd_completion_handler->run(
 					cmd_completion_handler->data);
 			if (completion_code != LTTNG_OK) {
-				clean_command_ctx(&cmd_ctx);
 				continue;
 			}
 		}
@@ -2379,12 +2426,24 @@ static void *thread_manage_clients(void *data)
 		health_code_update();
 
 		if (sock >= 0) {
+			struct lttng_payload_view view =
+					lttng_payload_view_from_payload(
+							&cmd_ctx.reply_payload,
+							0, -1);
+			struct lttcomm_lttng_msg *llm = (typeof(
+					llm)) cmd_ctx.reply_payload.buffer.data;
+
+			assert(cmd_ctx.reply_payload.buffer.size >=
+			       sizeof(llm));
+			assert(cmd_ctx.lttng_msg_size == cmd_ctx.reply_payload.buffer.size);
+
+			llm->fd_count = lttng_payload_view_get_fd_handle_count(&view);
+
 			DBG("Sending response (size: %d, retcode: %s (%d))",
-					cmd_ctx->lttng_msg_size,
-					lttng_strerror(-cmd_ctx->llm->ret_code),
-					cmd_ctx->llm->ret_code);
-			ret = send_unix_sock(sock, cmd_ctx->llm,
-					cmd_ctx->lttng_msg_size);
+					cmd_ctx.lttng_msg_size,
+					lttng_strerror(-llm->ret_code),
+					llm->ret_code);
+			ret = send_unix_sock(sock, &view);
 			if (ret < 0) {
 				ERR("Failed to send data back to client");
 			}
@@ -2394,10 +2453,8 @@ static void *thread_manage_clients(void *data)
 			if (ret) {
 				PERROR("close");
 			}
-                }
-                sock = -1;
-
-		clean_command_ctx(&cmd_ctx);
+		}
+		sock = -1;
 
 		health_code_update();
 	}
@@ -2412,7 +2469,6 @@ error:
 	}
 
 	lttng_poll_clean(&events);
-	clean_command_ctx(&cmd_ctx);
 
 error_listen:
 error_create_poll:
@@ -2430,7 +2486,7 @@ error_create_poll:
 	health_unregister(health_sessiond);
 
 	DBG("Client thread dying");
-
+	lttng_payload_reset(&cmd_ctx.reply_payload);
 	rcu_unregister_thread();
 	return NULL;
 }